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 Post subject: Titanium 600.2 Help Needed
PostPosted: Thu Aug 01, 2019 7:45 am 

Joined: Thu Aug 01, 2019 7:25 am
Posts: 6
Hi All Phoenix Gold Experts!

I need help with the repair of a Titanium 600.2. It is the same old story that you have all heard in this forum, someone has worked on this before and did not really do a great job. I received the amp with a completely blown power supply section, one dead 2SC5200, allot of screws in the wrong places/missing, dirt and foreign objects between semi conductors and heat sinks, etc., etc.

The blown 2SC5200, had no heat sink attached and when I finished disassembly I understood why. A previous person broke the mounting bolt off in the threaded PCB insert.

Where on earth would I find one of these heat sinks? And has anyone replaced one of these inserts before and can tell be where to find it?

Thank you all so much!


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File comment: Broken 4-40 Bolt
IMG_3865_Cropped.jpg
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File comment: Missing Heat Sink
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IMG_3859_Cropped.jpg [ 1015.54 KiB | Viewed 565 times ]
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 Post subject: Re: Titanium 600.2 Help Needed
PostPosted: Tue Aug 06, 2019 3:12 pm 
Mad Scientist
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Joined: Sat Apr 19, 2008 11:57 pm
Posts: 1469
Location: Beaverton 48612
They are #4-40 solder nuts. I believe you can get them from any of the electronics suppliers or McMaster Carr. They can be desoldered, but they are also splined and pressed into the fr4. If you get the solder of, they will press out pretty easily. You should also try to remove all the solder from the bottom of the nut as well. They are through holes even though many times there is solder covering the bottom. There is a chance you will be able to get the screw out from the bottom side, remove the solder and then try drilling it from the bottom with a standard right hand twist drill.



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M: M100, M44 for a custom amp project
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 Post subject: Re: Titanium 600.2 Help Needed
PostPosted: Tue Aug 13, 2019 9:37 am 

Joined: Thu Aug 01, 2019 7:25 am
Posts: 6
Thank you Mad Scientist!

I was able to get the insert situation resolved and it looks like I should be able to tighten a new screw. Like you said, there were multiple inserts that had solder on the bottom and I think that also made some of the screws not clamp the heat sink as designed. Further contributing to the thermal problems that caused the amp to fail.

There were several cases where 1/8W resistors were also clipped and re-soldered, further evidence that this amp has been worked on before.

The biggest issue I am facing at the moment is that the right channel bias circuit does not seem to be working. While the left had can be set as expected, the right hand hardly makes any difference, full range. I have tested the trimmer, since I know they fail, but this one seems to be fine. I have reviewed the schematic for the MS2125 (since this is the only schematic I could find and it does seem similar) and cannot figure out where to look for the problem.

Any advice?
Any high resolution pictures of a ti600.2 that has not been worked on before?

Thanks again!


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 Post subject: Re: Titanium 600.2 Help Needed
PostPosted: Tue Aug 13, 2019 9:44 am 

Joined: Thu Aug 01, 2019 7:25 am
Posts: 6
I still wanted to mention that I was going to try and use this for the missing heat sink

https://www.mouser.com/ProductDetail/532-575703B00

Thoughts?


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 Post subject: Re: Titanium 600.2 Help Needed
PostPosted: Tue Aug 13, 2019 11:42 am 

Joined: Sat Aug 06, 2011 1:18 am
Posts: 100
looks good!


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 Post subject: Re: Titanium 600.2 Help Needed
PostPosted: Wed Aug 14, 2019 5:17 am 

Joined: Thu Aug 01, 2019 7:25 am
Posts: 6
Thank you for the input Silverhorse!

I also got the bias circuit sorted out. I was looking for component failure, I should have been looking for mechanical failure :roll:

Q123 had both pin 1 and 3 broken. For a temporary fix (to make sure I have all the problems sorted out for that channel) I have attached new leads for now.

I cannot find the original parts for the drivers 2sC5248, but have some KTC4370A and KTC1659A (complimentary) on hand, would this be suitable?

Also, is there any reason not to use MJL3281A (NPN) and MJL1302A (PNP) instead of the 2SC5200 (NPN) and 2SA1943 (PNP) if I have those on hand? The only thing from the data sheets that I can find is that at 100 degree C, the MJLs are still rated at higher dissipation than the 2S devices.

Again, all help appreciated!!


Attachments:
File comment: Data Sheet KTC1659A
KEC-Semicon-KTA1659A-Y-U-PF_C69800.pdf [456.48 KiB]
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File comment: Data Sheet KTC4370A
KEC-Semicon-KTC4370A-Y-U-PF_C125308.pdf [456.32 KiB]
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IMG_4273_Cropped.jpg
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 Post subject: Re: Titanium 600.2 Help Needed
PostPosted: Mon Aug 19, 2019 4:44 am 
Mad Scientist
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Joined: Sat Apr 19, 2008 11:57 pm
Posts: 1469
Location: Beaverton 48612
There are multiple different screw lengths used to secure the isolation plates and heat sinks. Probably the po just jammed them in every which way. My personal favorite is when they run the long ones in over the peer supply and drive them down into the board... There is no shortage of stupid around...

There is a thread right above or below this where I gave a member a list of several subs for transistors in this amp. The MJL parts will work fine, so will the Fairchild equivalent ones.

Make sure that if someone removed the flame proof resistors in the poweramp, that you replace them with the correct parts. You can tell the stock flameproof parts by their color and they have an additional color band that won't make sense. I'd compare channel to channel to see if any were replaced. The ms schematic you found will show the flameproof locations as a circle with a "F" inside of it ( f ).



_________________
M: M100, M44 for a custom amp project
Zx: Zx500, Zx450, Black Zx350
ZxTi: 4 Zx600Ti's, 1 Zx400Ti
Ti: 5 800.1's & 900.7 for a custom amp project. 1 1200.1, 1 1000.2
Tantrum: 2 1200.1's, 1 600.4, 1 500.2
XS: XS6600
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 Post subject: Re: Titanium 600.2 Help Needed
PostPosted: Mon Aug 19, 2019 4:47 am 
Mad Scientist
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Joined: Sat Apr 19, 2008 11:57 pm
Posts: 1469
Location: Beaverton 48612
That heat sink will work, but you'll have to drill the center hole. The style is technically meant to mount under a to-3 transition



_________________
M: M100, M44 for a custom amp project
Zx: Zx500, Zx450, Black Zx350
ZxTi: 4 Zx600Ti's, 1 Zx400Ti
Ti: 5 800.1's & 900.7 for a custom amp project. 1 1200.1, 1 1000.2
Tantrum: 2 1200.1's, 1 600.4, 1 500.2
XS: XS6600
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 Post subject: Re: Titanium 600.2 Help Needed
PostPosted: Tue Aug 20, 2019 4:12 pm 

Joined: Thu Aug 01, 2019 7:25 am
Posts: 6
Thanks Mad Scientist,

I did look through the treads to determine which devices are recommended and that is how I made the selection for the Drivers also.

Ditto on the screws. This Amp was a MESS with the screws in the wrong places. Like you said, long screws in the power supply, which was not even tightened down properly because of this!

I have the flame proof resistors on order and will replace all I can find between the schematic and the other channel. Another thing that was a challenge is that someone cut out resistors and then soldered them back, BADLY, so I have to replace some in the voltage amplification stage also. The originals may have been 1/8w and I will use the 1/4 that I have on hand.

I am planning to drill the heat sink to make it fit.

I have also found a good way to bend the leads of the output transistors reliably and consistently. I find an hex key of the correct size (5mm worked well), keep a flat side to the leads as close to the body as possible and bend the leads around it. No sharp corners and the bend is actually made it two sections.

To solder the transistors onto the board I secured them with an old one and then made sure the leads had NO STRESS prior to soldering.

Also, here is a link to the cooling fans, the one I had did not work https://www.newark.com/adda/ad0812hb-d7 ... dp/45T0214


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File comment: Securing Transistor
IMG_4380_Cropped.jpg
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